feat(webidl): support signed short argument conversion

moli-webidl-derive/src/converter.rs

@@ -15,6 +15,7 @@ pub(crate) enum ConverterKind {
     CallbackInterface,
     Long,
     EnforceRangeLong,
+    Short,
     UnsignedShort,
     ClampedUnsignedShort,
     UnsignedLong,
@@ -45,6 +46,7 @@ impl ConverterKind {
             "callback_interface" => Ok(Self::CallbackInterface),
             "long" => Ok(Self::Long),
             "enforce_range_long" => Ok(Self::EnforceRangeLong),
+            "short" => Ok(Self::Short),
             "unsigned_short" => Ok(Self::UnsignedShort),
             "clamped_unsigned_short" => Ok(Self::ClampedUnsignedShort),
             "unsigned_long" => Ok(Self::UnsignedLong),
@@ -74,6 +76,7 @@ impl ConverterKind {
             Self::CallbackInterface => quote!(::moli_webidl::WebIdlCallbackInterface),
             Self::Long => quote!(::moli_webidl::Long),
             Self::EnforceRangeLong => quote!(::moli_webidl::EnforceRangeLong),
+            Self::Short => quote!(::moli_webidl::Short),
             Self::UnsignedShort => quote!(::moli_webidl::UnsignedShort),
             Self::ClampedUnsignedShort => quote!(::moli_webidl::ClampedUnsignedShort),
             Self::UnsignedLong => quote!(::moli_webidl::UnsignedLong),
@@ -110,6 +113,7 @@ impl ConverterKind {
             Self::CallbackFunction | Self::CallbackInterface => quote!(#expr),
             Self::Long => quote!(::moli_webidl::Long(#expr)),
             Self::EnforceRangeLong => quote!(::moli_webidl::EnforceRangeLong(#expr)),
+            Self::Short => quote!(::moli_webidl::Short(#expr)),
             Self::UnsignedShort => quote!(::moli_webidl::UnsignedShort(#expr)),
             Self::ClampedUnsignedShort => {
                 quote!(::moli_webidl::ClampedUnsignedShort(#expr))
@@ -141,6 +145,7 @@ impl ConverterKind {
             | Self::UsvString
             | Self::Long
             | Self::EnforceRangeLong
+            | Self::Short
             | Self::UnsignedShort
             | Self::ClampedUnsignedShort
             | Self::UnsignedLong
@@ -242,6 +247,9 @@ fn infer_converter_kind(ty: &Type) -> Option<ConverterKind> {
     if is_type_ident(ty, "u16") {
         return Some(ConverterKind::UnsignedShort);
     }
+    if is_type_ident(ty, "i16") {
+        return Some(ConverterKind::Short);
+    }
     if is_type_ident(ty, "u64") {
         return Some(ConverterKind::UnsignedLongLong);
     }

moli-webidl/src/convert.rs

@@ -261,6 +261,21 @@ impl<'s> WebIdlConverter<'s> for EnforceRangeUnsignedLong {
     }
 }
 
+impl<'s> WebIdlConverter<'s> for crate::Short {
+    type Options = ();
+
+    fn convert(
+        scope: &mut v8::PinScope<'s, '_>,
+        value: v8::Local<'s, v8::Value>,
+        context: Context,
+        _options: &Self::Options,
+    ) -> Result<Self, WebIdlError> {
+        // Both 16-bit integer types truncate and reduce modulo 2^16; signed
+        // short then interprets the high bit as a negative value.
+        number_value(scope, value, context, "short").map(|value| Self(unsigned_short(value) as i16))
+    }
+}
+
 impl<'s> WebIdlConverter<'s> for UnsignedShort {
     type Options = ();
 

moli-webidl/src/lib.rs

@@ -64,8 +64,8 @@ pub use traits::{ParseOutcome, WebIdlArguments, WebIdlConverter, WebIdlDictionar
 pub use types::{
     Boolean, BufferSource, ByteString, ClampedUnsignedShort, DomString, DomString16, Double,
     EnforceRangeLong, EnforceRangeUnsignedLong, EnforceRangeUnsignedLongLong, EnumValue,
-    EventListenerOptions, Long, Record, Sequence, StringOptions, UnrestrictedDouble, UnsignedLong,
-    UnsignedLongLong, UnsignedShort, UsvString,
+    EventListenerOptions, Long, Record, Sequence, Short, StringOptions, UnrestrictedDouble,
+    UnsignedLong, UnsignedLongLong, UnsignedShort, UsvString,
 };
 
 /// Restricted WebIDL float represented as a finite binary32 value.

moli-webidl/src/types.rs

@@ -227,6 +227,15 @@ impl From<EnforceRangeUnsignedLong> for u32 {
     }
 }
 
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub struct Short(pub i16);
+
+impl From<Short> for i16 {
+    fn from(value: Short) -> Self {
+        value.0
+    }
+}
+
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 pub struct UnsignedShort(pub u16);
 

moli-webidl/tests/short.rs

@@ -0,0 +1,93 @@
+use moli_webidl::WebIdlArgs;
+
+#[derive(WebIdlArgs)]
+#[webidl(prefix = "Test.short")]
+struct InferredShortArgs {
+    #[webidl(required)]
+    value: i16,
+}
+
+#[derive(WebIdlArgs)]
+#[webidl(prefix = "Test.explicitShort")]
+struct ExplicitShortArgs {
+    #[webidl(required, converter = "short")]
+    value: i16,
+}
+
+fn inferred_short<'s>(
+    scope: &mut v8::PinScope<'s, '_>,
+    args: v8::FunctionCallbackArguments<'s>,
+    mut rv: v8::ReturnValue<'s>,
+) {
+    if let Some(parsed) = moli_webidl::parse_args::<InferredShortArgs>(scope, &args) {
+        rv.set(v8::Number::new(scope, f64::from(parsed.value)).into());
+    }
+}
+
+fn explicit_short<'s>(
+    scope: &mut v8::PinScope<'s, '_>,
+    args: v8::FunctionCallbackArguments<'s>,
+    mut rv: v8::ReturnValue<'s>,
+) {
+    if let Some(parsed) = moli_webidl::parse_args::<ExplicitShortArgs>(scope, &args) {
+        rv.set(v8::Number::new(scope, f64::from(parsed.value)).into());
+    }
+}
+
+#[test]
+fn signed_short_wraps_and_preserves_conversion_errors_in_the_callee_realm() {
+    moli_v8_test_util::ensure_v8();
+    let mut isolate = v8::Isolate::new(v8::CreateParams::default());
+    let scope = std::pin::pin!(v8::HandleScope::new(&mut isolate));
+    let scope = &mut scope.init();
+    let callee = v8::Context::new(scope, Default::default());
+    let values = {
+        let scope = &mut v8::ContextScope::new(scope, callee);
+        let inferred = v8::Function::new(scope, inferred_short).unwrap();
+        let explicit = v8::Function::new(scope, explicit_short).unwrap();
+        let key = v8::String::new(scope, "TypeError").unwrap();
+        let error = callee.global(scope).get(scope, key.into()).unwrap();
+        [
+            ("inferred", inferred.into()),
+            ("explicit", explicit.into()),
+            ("CalleeTypeError", error),
+        ]
+    };
+    let caller = v8::Context::new(scope, Default::default());
+    let scope = &mut v8::ContextScope::new(scope, caller);
+    for (name, value) in values {
+        let key = v8::String::new(scope, name).unwrap();
+        assert_eq!(
+            caller.global(scope).set(scope, key.into(), value),
+            Some(true)
+        );
+    }
+    let source = v8::String::new(scope, r#"
+        (() => {
+          const assert = (ok, message) => { if (!ok) throw Error(message); };
+          const values = [[0,0],[-0,0],[3.9,3],[-3.9,-3],[32767,32767],
+            [32768,-32768],[65535,-1],[65536,0],[65537,1],[-65537,-1],
+            [4294967295,-1],[4294967297,1],[NaN,0],[Infinity,0],[-Infinity,0],
+            [undefined,0],[null,0],[true,1],['65535',-1]];
+          for (const convert of [inferred, explicit]) {
+            for (const [value, expected] of values) assert(Object.is(convert(value),expected),'modulo conversion '+value);
+            for (const value of [Symbol('number'), 1n]) {
+              let error;try { convert(value); } catch(caught) { error=caught; }
+              assert(error instanceof CalleeTypeError && !(error instanceof TypeError),'callee realm TypeError');
+            }
+            let reads=0;const value={[Symbol.toPrimitive](hint){reads++;assert(hint==='number','numeric hint');return 65535;}};
+            assert(convert(value)===-1&&reads===1,'one observable conversion');
+            const sentinel={};let error;try{convert({valueOf(){throw sentinel;}});}catch(caught){error=caught;}assert(error===sentinel,'exception identity');
+            try { convert(); } catch(caught) { error=caught; }assert(error instanceof CalleeTypeError,'required argument');
+          }
+          return true;
+        })()
+    "#).unwrap();
+    let script = v8::Script::compile(scope, source, None).unwrap();
+    assert!(
+        script
+            .run(scope)
+            .expect("signed short conversion matrix")
+            .is_true()
+    );
+}